<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>4.传统⽅式布局微信客户端界⾯</title>
  <style>
     * {
      padding :0;
      margin: 0;
    }
    /*传统方式布局，每次底部按钮增加*/
    main {
      height: 100vh;
      background: #ddd;
    }
    footer {
      position: fixed;
      height: 50px;
      bottom: 0;
      width: 100vw;
      height: 50px;
      background: linear-gradient(to bottom,#f3f3f3,#ddd,#f3f3f3 );
      border-top: solid 1px #ddd;
    }

    footer div {
      float: left;
      width: 25%;
      height: 100%;
      box-sizing: border-box;
      text-align: center;
      line-height: 3em;
      color: #555;
    }
    footer div:nth-child(n+2) {
      border-left: solid 1px #ddd;
    }
    /*flex*/
  </style>
</head>
<body>
  <!-- 传统方式 -->
  <main></main>
  <footer>
    <div>后盾人</div>
    <div>直播</div>
    <div>教程</div>
    <div>444</div>
  </footer>
  <!-- flex -->
</body>
</html>